as a long term reader of this forum, I finally decided to become an active member and start posting threads. I collected some questions, this bunch of experts surely can help me answering

In our last session, the question came up, how the cameras of a traffic monitoring system of large cities are secured. I assume that cities like Hamburg or Seattle have huge amounts of cameras for the surveillance of the traffic. I see in principle three possibilities doing this:
1. Connect all cameras by wire. In SR4, this sounds not very reasonable, since everything seems to be wireless. In addition, the network would be rather expensive.
2. Use very secure (and therefore expensive) nodes to access the cameras. I assume every camera to be a kind of commlink, you can hack in, so the firewall should be not too low to prevent the intrusion of script-kiddies.
3. Put the cameras in a master-slave connection with a central node. Sounds good, but as far as I know, the limit is System x2 subscriptions, so for the thousands of cameras, hundreds of central commlinks would be necessary!?
What I actually want to know is, how to hack into these cameras. Can I hack a single camera (option 2), or do I have to break into the central node (option 3 and maybe 1)?